Optical storage technology is widely used in general life, and representative examples thereof include a Compact Disc (CD), Digital Versatile Disc (DVD), Blu-ray, and the like. The quantity of data to be recorded in an optical storage device is increasing thanks to the dissemination of high-quality images, and the development of the optical storage device is being conducted with the goals of increased integration, size reduction, and weight reduction, in order to enable a great quantity of data to be recorded.
In addition, there is a demand for a holographic storage medium, which is advantageous in size reduction and is strongly resistant to external shocks, in order to ensure that the optical storage device is attachable to a mobile appliance so as to increase the utility thereof. This requires a structural change in a conventional disc-shaped optical storage device.
A holographic data storage system using a hologram has been studied for application to optical storage methods in consideration of the recent trend toward high integration and size reduction.
The holographic data storage system is based on the principle of recording and reading data in page units, and therefore has advantages of fundamentally increasing a data transmission rate and theoretically realizing a storage density of 1 Tbit/cm2 through the use of a parallel data processing method that uses, for example, an LCD, CCD (or CMOS) as an input/output device.
In the holographic data storage system, the core principle of enabling high density recording comes from the fact that data can be recorded in an overlapping manner in the same location on a holographic storage medium, without requiring spatial isolation. This method is referred to as a multiplexing technique, and in particular, an angle multiplexing technique has been the most widely used, in which two kinds of light are emitted at different angles so that data is recorded in an overlapping manner.
However, the holographic data storage system has been difficult to commercialize due to the large volume thereof, and thus studies with the goal of minimizing the volume thereof are being conducted.